Abstract: The spatial distribution of particle fluences in the extended uranium target (“Quinta” assembly) irradiated by 0.66 GeV proton, 4 AGeV deuteron and carbon beams is studied by analyzing the accumulation rates of the isotopes with different threshold energy (E) in Co samples. The accumulation rates for the following isotopes: Co (E 0 MeV), Fe (E 3 MeV), Co (E 10 MeV), Co (E 20 MeV), Co (E 32 MeV), Sc (E 55 MeV) , and V (E 70 MeV) were measured using the HPGe spectrometer. The experimental accumulation rates and the reconstructed neutron spectra are compared with the simulations using the codes Geant4 and MARS15. The noticeable difference between the simulated and the experimental data, especially in the hard part of the neutron spectrum, is analyzed.